Poking holes in the Gravity trailer with NASA’s help

We sit down with the guy who trains spacewalkers to see what's right—and wrong.

I haven't seen Alfonso Cuarón's Gravity yet, but I want to. The movie will enter general release here in the US on October 4. It stars George Clooney and Sandra Bullock as two astronauts having what looks to be a really, really bad day in space. Trailers for the movie show them flying around in their space suits, yelling and crying and dodging debris from exploding satellites and space ships and space stations, all lit by a beautifully rendered and untouchably distant Earth in the background.

The director and the studio have taken great pains to recreate the experience of operating in microgravity as accurately as possible. Cuarón consulted with NASA astronauts on the particulars of moving in microgravity, and, according to the NY Daily News, the movie's production designers studied thousands of NASA photographs in order to make their vision of space look authentic.

When asked how far that commitment to verisimilitude stretched, though, Cuarón said that while the movie strives for accuracy, "it would be disingenuous to say we did it 100 percent, because this is a movie, and we needed to take certain liberties."

The five minute-plus extended trailer for Gravity. Keep this video handy, because we're going to give it the MST3k treatment in just a moment.

There was a five-minute "extended trailer" for the movie published last month. It certainly had some gripping visuals, but the longer it went on, the deeper my frown became. I don't claim to be an expert, but the stuff that George Clooney and Sandra Bullock were doing on the screen just didn't look right. Certainly cool, but not right.

But this is Ars, and on certain things, we have the hook up. I may not be the expert, but I knew someone who was, and I was going to ask for his official opinion on that extended trailer.

The man who makes the plan

The last time I talked with Zeb Scoville was at NASA's Neutral Buoyancy Lab, the enormous indoor pool where NASA trains its astronauts on how to spacewalk—or, more properly, how to function during extravehicular activity, or EVA. Scoville is the EVA task group lead at the NBL, and he is responsible for managing the teams that figure out how EVAs work. If an EVA's goal is to replace a part outside the space station, for example, Scoville figures out exactly what the astronauts need to do to replace the part, including the physical movements they need to make. His team is made up of actual NASA flight controllers—during training at the pool, they run the simulations, and during the actual missions, they're manning the consoles in Mission Control.

Enlarge/ NASA EVA Task Group manager Zeb Scoville, standing in one of the test coordinator control rooms at the Neutral Buoyancy Laboratory. Visible behind him is the NBL pool.

Steven Michael

If anyone could shed some light on the accuracy or inaccuracy of Clooney and Bullock's space antics, I figured Scoville would be the man. After a quick call to NASA's press office to arrange some time to talk, we sat down together to watch our way through the trailer.

Problem: debris

The trailer kicks off with an EVA in progress, and a radio-distorted voice is heard calling for an abort. It becomes clear that the message is directed at some astronauts working on something outside their spacecraft. It looks like they're repairing the Hubble Space Telescope, though it might be something else—for instance, some KEYHOLE reconnaissance satellites are said to share the Hubble's external form factor. Whatever it is, the astronauts are outside with big debris incoming, which means they're in trouble.

Enlarge/ Screencap from the trailer, showing the start of a giant debris storm. Note the monstrous size of the piece of debris near frame center.

Warner Bros

Right away, the sheer size of the debris gave us pause. NASA relies on US Strategic Command's big radars to keep constant radar watch on its vehicles, and the chunks shown on-screen are far larger than the minimum size that USSTRATCOM would notice. "Part of the procedure for getting ready for an EVA would include checking for debris like this, wouldn't it?" I asked.

"Right—we have a process that's known as a 'certification of EVA readiness,'" answered Scoville. "We have the EVA community come together, and they'll present a lot of the technical analysis, and we give our community-wide consensus for a 'go' for the EVA." Scoville explained that this analysis includes an assessment of the risk of encountering orbital debris during the EVA. Space isn't empty, especially at the International Space Station's low altitude, and there's always the chance that there'll be a "conjunction," NASA-speak for a potential collision between debris and a vehicle or astronaut. Debris risk is assessed in terms of the potential damage—whether the expected amount of debris could cause a suit leak small enough to survive (which would terminate the mission), or whether it could cause loss of a spacecraft or even astronaut lives.

"The debris they have there is orders of magnitude larger than what you need to create a very catastrophic puncture in a space suit. For comparison, if you have up to about an eighth inch of a hole in an EMU"—that's Extravehicular Mobility Unit, NASA's acronym for a spacesuit—"it has emergency oxygen systems which can feed that leak and maintain pressure for about 30 minutes to get you back inside the airlock and repress the airlock. Above about an eighth of an inch, and it can't maintain pressure."

"Is there a procedure for what to do if that happens?" I asked. "Like, you stick your finger in the hole or try to squeeze the leak closed?"

Scoville responded in the negative because of the spacesuit's many-layered structure. "On the inside, you have the bladder layer, that actually maintains the pressure of the suit. Beyond that there's the restraint layer, and then you have a neoprene layer, and beyond that the insulation mylar layers for heat rejection, with layers of scrim in between for separation, then the white Ortho-Fabric on the outside. No matter how much you squeeze or push on the outer layer, you're not getting to the inner layer where the bladder is. You wouldn't be able to seal that with a gloved hand with 4.3 pounds of pressure trying to get out of the suit."

Although an EVA wouldn't be allowed to happen under such conditions, Scoville speaks up here and lets me know that he's actually Googled a plot summary of the movie in preparation for our talk. The debris in Gravity actually comes from an event that occurs after the EVA has started. Under such circumstances, the EVA would indeed be terminated, just as is depicted in the trailer. I stow my nerd rage, and we continue.

Problem: Clooney's jetpack

After the debris zips past, intrepid astronaut George "The Chin" Clooney comes in frame, sporting a very cool space jetpack. There's a problem with that backpack, though—nothing like it exists in NASA's active inventory anymore. To me, it looks like Clooney's character is supposed to be wearing a Manned Maneuvering Unit or MMU, a piece of equipment developed for shuttle astronauts to use while repairing satellites. The MMUs worked great, but they weren't used very much, and NASA discontinued flying them in the 1990s. They weren't re-introduced for use on the International Space Station because they're too large and bulky.

I point this out to Scoville. "Yeah," he replied. "It looks not quite like a MMU, but it's something close to it. Those things, the manned maneuvering units, are no longer used. In some of those shots, it looks like a cross between a MMU and a thing we call SAFER, which stands for 'Simplified Aid for EVA Rescue,' which is similar to a MMU—except it doesn't have the same level of redundancy, it's not as large, the joystick is a little different, and it doesn't hold as much gas."

The SAFER backpacks are for astronauts working around the International Space Station, and as the acronym suggests, they're intended to be used in case an astronaut accidentally drifts away from the station. Scoville explains that the little safety jetpack has 24 thrusters powered by the venting of compressed nitrogen gas, and it can accelerate an astronaut up to about 10 feet per second. The SAFER also has a smart gyro-based stabilization system that will automatically stop an astronaut from tumbling. However, these packs aren't intended to be used as the primary means for flitting about outside. The limited amount of delta-v the backpacks can impart is more than enough to stop a drifting astronaut, but the amount of propellant is very limited.

SAFER backpacks weren't used on shuttle missions, either: "On shuttle missions, when they weren't docked to station, they didn't need this—they could just fly the shuttle after them to pick them up if they fell off." This provides one explanation for why Clooney's character is wearing a jetpack and Bullock's character isn't—when we meet her in a moment, she's strapped into the foot restraints at the end of the space shuttle's remote manipulator arm, busily working away at repairing the telescope.

166 Reader Comments

I saw my first 3D film this week. I still think it's gimmicky, but boy did I have a lot of fun watching it. Still, if I see this in the theater, I'll probably stick to 2D+time.

I don't normally rate 3D movies, but this was definitely great to watch in 3D. When there's debris flying around it's actually pretty freaky; I honestly did perform a few dodging manoeuvres without meaning to!

I watched this today at 10:00am in a special pre-screening given by Dell where they started out showing us their new blade chassis/storage solution and their new top-line SSD SAN. Those two presentations were probably the best part of the showing. The movie itself has great effects, the graphics are above-par, and the 3D is very nice.

Beyond that it pales. Those that argue "I go to watch X and don't care about realism" -- that's easy to toss about but I disagree. I like realism to the extent that the plausibility within the world portrayed lends credence to the story. I did not find myself attached to the characters in this movie and had a harder time enjoying the Scare->suspense->resolution->repeat plot-line when the plot holes made it difficult to suspend disbelief.

The majority of the people I watched the movie with were IT geeks and not many people thought it was great. In fact there was a lot of head-shaking. Were we too critical when we love Game of Thrones and Star Trek? Sure, probably -- but at least those movies try to adhere to canon and explain most things as fitting within the universe. If warp engines were powered by coal, we might find it much more idiotic.

In the same regard, this movie had way too many head-scratchers that I can't go into without spoiling that pushed any viewer with a modest amount of trivial space knowledge out of the aforementioned 'suspension of disbelief' zone. To each their own! If I had gone into the movie just expecting it for what it is, an artful suspense drama that just happened to have space as a backdrop I might have enjoyed it more.

In the trailer, the manipulator arm goes flying off into space with Sandra attached. When she unhooks, SHE shoots away from the arm. Am I wrong in thinking that when she unhooks, she would stay right there with the arm? Maybe slowly drift away from it, not be shot out like it's a catapult?

Why is everyone so quick to try to find this movies failures? It looks to be a really exciting, and thrilling movie. Why destroy it before people see it - not based on the quality of the movie itself, but the science. Last time I checked this was not a documentary...

probably for the same reasons that climate scientists were doing the same for 2012 and the day after tomorrow. When it's your field of interest then you "like" to see it shown accurately

I think it's incredibly precious to expect a non-documentary film on general release to the unwashed masses to represent one's field with 100% accuracy.

Name one film released this side of 2000 that was 100% accurate. Most of them are at about 20%, and scifi at about 1%. If a film hits even 80% it's done a spectacular job.

Repeat after me: fiction isn't fact.

Are you saying that Lord of the Rings is not accurate? Geez, I was so hoping to visit Middle Earth for a vacay. Thanks for ruining my dream.

All joking aside, I'm okay with movies taking some liberties with the science so long as it tells a good story. This is one of the reasons I avoid most horror movies now, they're all the same story with all the same cliched actions and sequences that they just aren't appealing to me anymore.

For space movies, I'm okay with not being entirely accurate since the only way to show that is to get actual footage of what happens in space.

In the trailer, the manipulator arm goes flying off into space with Sandra attached. When she unhooks, SHE shoots away from the arm. Am I wrong in thinking that when she unhooks, she would stay right there with the arm? Maybe slowly drift away from it, not be shot out like it's a catapult?

Shooting away is fine. Forget the army's lateral motion for a second and focus on it's spinning. When she disconnects she'll be moving at the rotation speed, but now nothing is pulling her motion into an arc -- the end of the arm will continue to rotate, but now she'll be traveling in a straight line at the rotation speed. It's exactly like spinning a rock on a rope, then having the rock break free.

Then add back in the lateral motion of the arm. She'll still have that.

I do agree with some other commenters that it looks like she heads in the wrong direction upon releasing, though.

"Meetings would become irrelevant at that point," he replied. "It would be more like, do we as a species want to continue to fly into space, and make it a priority to rebuild that capability."

That scares me more than anything. Most people do not realize how much of our current technological status is due to the technical accomplishments related to space programs. Not to mention the insanity of being a one-planet sentient species.

On the arm-spin: She goes flying away attached to about half the Canadarm. I can't find much information on exactly how much each segment masses, but the arm itself masses [url=http://www.asc-csa.gc.ca/eng/canadarm/description.asp]410kg/url]], so let's say she's attached to 200kg of arm. The Shuttle EMU masses a good 125kg all-up (but without tools), plus an average human female mass of 60kg, for a total of 185kg. That's pretty close! Back-of-the-napkin gives that the centre of rotation should be around 1/4 of the way down the arm fragment from our Bullocknaut, so ~1.9m from her (1/4 of 1/2 a 15m Canadarm). Moment of inertia would be about 670kgm^2, rotation rate at the point she detaches is about π rad/s, so an angular momentum of 2105Nms, and a release velocity of 10 m/s.

Not sure what that shows really, but that's half an hour of work I've avoided by looking up definitions I'd long forgotten!

Checking the accuracy of a film's science, and using both those places where it is accurate and those places where it is inaccurate as a point of reference for talking about the science, is absolutely about having an interest in science! I mean look at the discussion on transferring orbital planes -- how is that not interesting?

Oh, it might be interesting. And that might be why some people do it. But not everyone.

Do you think when police complain about accuracy in police films it's because they are interested in policing? Or do you think it's a group social behaviour used to help group definition and cohesion and refine intragroup rankings?

The nit-picking is only really obnoxious when "scientific accuracy" is used as the sole criterion for whether the movie is any good, where any failing means the movie is crap. Which is not what's happening here.

I completely disagree. There is some discussion here, sure, and that is indeed interesting to an extent (*) but also a lot of dismissal. Here's one of the earliest comments, the one that got me started "discussing".

Quote:

If your error could have been solved by 30 seconds on Wikipedia, then that's not making a vital deviation to allow the plot to advance, it's just not caring. And not caring about your film is rarely the sign of a good film.

Pointless, nerdy snark about fact-checking, with a massive factual inaccuracy in it. Too busy displaying his all-conquering his brain to understand that the panicky person is not an astronaut.

Here's another:

Quote:

they just couldn't resist adding sound in space, eh?

No. Because it's entertainment. You wouldn't have a laser battle without drawing in the lasers, because it doesn't work as entertainment. Nit-picking from someone who clearly doesn't understand how entertainment works.

Something I think is being missed in all this talk of nit-picking is just how much of the 5-minute trailer they got right. Pretty impressive! Normally in a trailer like this you'd be hard pressed to find anything that was actually correct scientifically.

That point has already been made. For a film to even hit 80% accuracy is pretty impressive. These things have to entice and entertain people, to make money.

If we nerd-out and nitipick, make sci-fi seems like a physics lesson, scare off your average joe, reduce profits, scare off investors ... no more sci-fi.

You wouldn't have a laser battle without drawing in the lasers, because it doesn't work as entertainment.

Has anyone tried? Yes, people expect lasers to be pew-pew shiny walking-pace beams of colour thanks mailnly to Star Wars and Star Trek, but that doesn't preclude a realistic depiction being impressive. An invisibly sourceless explosion of flesh-flashed-to-steam smites anyone who looks around a corner? Terrifying! An invisible 'heat ray' causes a line of foliage to immolate advancing inexorably and quickly towards our heroes as the emitter tracks towards them? Suspense! You could even posit a hilariously powerful laser that filaments at the target region, bringing a blinding lance of plasma flashing into existence piercing the target. All seem like they'd make for dramatic and impressive scenes.

Saying a realistic depiction is impossible to make entertaining is a failure of imagination.

All joking aside, I'm okay with movies taking some liberties with the science so long as it tells a good story. This is one of the reasons I avoid most horror movies now, they're all the same story with all the same cliched actions and sequences that they just aren't appealing to me anymore.

For space movies, I'm okay with not being entirely accurate since the only way to show that is to get actual footage of what happens in space.

This.

We can toss aside notions of flux capacitors & time traveling DeLoreans and enjoy a movie that tells a great story. Same with light sabers, warp drives, and the lot.

Push that boundary (we can get this Macbook to interface with an alien spaceship, no problem!) and that's where a movie falls apart.

I saw Gravity today and I thought it did alright. It's unlikely that I'll watch it again, but it was a good way to spend two hours.

On that note, 1/8 inch is approximately 3mm for the mathematics-impaired.

Thanks, although the reason (non-US) people cannot calculate that is not because they cannot do math, but because they do not remember how much an inch is (since we never use it). It might be just as well 1/8 Fantastillion.

Push that boundary (we can get this Macbook to interface with an alien spaceship, no problem!) and that's where a movie falls apart.

Now this is a complaint that never made sense to me. It's an everyday occurence to interface with, and explot, one operating system with another, or one architecture with another (nobody thinks anything of using an exploit to escalate privileges on a Linux-based Android ARM-architecture device by using a program on a Windows-based x86 PC). Why is it so odd to write a driver to interface with a custom PCMCIA-aliennetwork card in order to inject your payload? It'd be more inconvenient to try and operate an entire alien computer by hand than to glom on your own interface.

Push that boundary (we can get this Macbook to interface with an alien spaceship, no problem!) and that's where a movie falls apart.

Now this is a complaint that never made sense to me. It's an everyday occurence to interface with, and explot, one operating system with another, or one architecture with another (nobody thinks anything of using an exploit to escalate privileges on a Linux-based Android ARM-architecture device by using a program on a Windows-based x86 PC). Why is it so odd to write a driver to interface with a custom PCMCIA-aliennetwork card in order to inject your payload? It'd be more inconvenient to try and operate an entire alien computer by hand than to glom on your own interface.

Push that boundary (we can get this Macbook to interface with an alien spaceship, no problem!) and that's where a movie falls apart.

Now this is a complaint that never made sense to me. It's an everyday occurence to interface with, and explot, one operating system with another, or one architecture with another (nobody thinks anything of using an exploit to escalate privileges on a Linux-based Android ARM-architecture device by using a program on a Windows-based x86 PC). Why is it so odd to write a driver to interface with a custom PCMCIA-aliennetwork card in order to inject your payload? It'd be more inconvenient to try and operate an entire alien computer by hand than to glom on your own interface.

From pretty much all the trailers I've seen of this movie, I get a sense of "Exactly how much space station is there to be destroyed over the course of an hour-long movie, especially while holding onto any chance of survival?" This is like the SAT-T1TAN1C, or something...

Slight tangent: That feeling of having the errors hit you, like when a space enthusiast watches a movie like this...that's basically how a lot of game designers/developers feel when playing many video games, unfortunately.

"What? So the tractor beam has a side effect of depleting your energy, which doesn't regenerate?...Your tutorial did NOT communicate all of that!""WHY did I need an objective marker there? Just let me explore - the objective is the most visually noticable location in this area!"

It certainly doesn't help me that I've also taken a film class, so it becomes even harder to turn my mind off and appreciate "mid-range" movies.

On that note, 1/8 inch is approximately 3mm for the mathematics-impaired.

Thanks, although the reason (non-US) people cannot calculate that is not because they cannot do math, but because they do not remember how much an inch is (since we never use it). It might be just as well 1/8 Fantastillion.

How can you not remember what an inch is? It's the the length of three barley-corn. So, an eighth of an inch is simply 3/8ths of a barley- corn. Next, you're going to tell me you never use barley-corn.

All joking aside, I'm okay with movies taking some liberties with the science so long as it tells a good story. This is one of the reasons I avoid most horror movies now, they're all the same story with all the same cliched actions and sequences that they just aren't appealing to me anymore.

That is exactly the reason you need to watch 4 or 5 horror movies, and then follow them up with Cabin in the Woods.

Getting on-topic, I think that what a lot of people don't seem to be getting here is that this article isn't about trashing the movie. It's about understanding the realities of space exploration, using the movie (or at least the trailer) as a point of reference that people are familiar with.

I mean look at the discussion on transferring orbital planes -- how is that not interesting?

Oh, it might be interesting. And that might be why some people do it. But not everyone.

What do you mean "might"? That discussion took place in the article. Was it interesting or not? I say "was". If you say "not", that's your viewpoint and says nothing about the motivation for the discussion.

Quote:

I completely disagree. There is some discussion here, sure, and that is indeed interesting to an extent (*) but also a lot of dismissal. Here's one of the earliest comments, the one that got me started "discussing".

If you're just talking about a subset of comments (and thus only partially disagree) then you should make that more clear. I didn't see you anything in your comment that made a distinction between certain comments, the rest of the comments, and the article itself. And so it is the article that I was talking about. Do you have an issue with that style of nit-picking the science in movies?

Quote:

Quote:

they just couldn't resist adding sound in space, eh?

No. Because it's entertainment. You wouldn't have a laser battle without drawing in the lasers, because it doesn't work as entertainment. Nit-picking from someone who clearly doesn't understand how entertainment works.

I'll take your implication that Stanley Kubrick and Joss Wedon (among others) don't understand how movies work under advisement. Which is a snarkier way of saying that it is certainly possible for a movie that accurately depicts the silence of space to also be entertaining.

If there's any movie at all that I would think would benefit from it, it'd be one that's intended to create a sense of isolation and fear about being trapped in the vacuum, a sort of "Open Water in Space". For a movie that's supposed to be trying to depict space with some level of accuracy, then this is the very first thing to do correctly. And there's no reason it can be made to work for the movie. Having the space-station blow up with nothing but the score accompanying it would only emphasize how "out-of-this-world" the place our protagonists are stuck is.

Hell, even the Stark Trek reboot exploited the silence of space to amazing dramatic effect... for 5 seconds. I really don't think the rest of the movie would have suffered if they'd continued.

Quote:

If we nerd-out and nitipick, make sci-fi seems like a physics lesson, scare off your average joe, reduce profits, scare off investors ... no more sci-fi.

So please, film nerds, STFU.

So, you do have an issue with the article, which was in part a physics lesson? Well whatever is all I have to say to that because this article was awesome. If someone didn't want that physics lesson -- or for that matter, any additional nit-picking in the comments -- they could have just not read it.

But I guess "average joe" isn't smart enough for that, and has to be protected from anything that sounds like actual science, anywhere on the internet because they'll stumble upon it, read it, become angry and frustrated that they can't understand it, and never watch a sci-fi movie again.

Frankly with that attitude I don't think you have any room to point fingers at other nerds acting smarter-than-thou.

Why is everyone so quick to try to find this movies failures? It looks to be a really exciting, and thrilling movie. Why destroy it before people see it - not based on the quality of the movie itself, but the science.

Actually, I thought the article was pretty laudatory for how well it didn't fail.

Why is everyone so quick to try to find this movies failures? It looks to be a really exciting, and thrilling movie. Why destroy it before people see it - not based on the quality of the movie itself, but the science. Last time I checked this was not a documentary...

Exactly. To this day, people complain about the historical innacuracies of "Pearl Harbor" (2001). I know the attack on Pearl Harbor was an actual historical event, but "Pearl Harbor" was not a documentary or a newsreel, it was a dramatic fictionalization, i.e., a movie! In the case of "Gravity", I will willingly suspend my disbelief to enjoy a 90-minute thrill-ride!

2001: A Space Odyssey has some excruciatingly slow scenes, and is still a fantastic movie 35 years later

It did, and it is, and I love it... but I completely understand that many people think it is boring.

The thing is it's not "boring" because he accurately depicted gravity in a space station, or the silence of space. It's "boring" because he chose to draw out so many of the shots. The only "action" in the movie, the murder of the one astronaut and his rescue by Dave, was fast-paced enough and seriously enhanced by the treatment of space. When the pod turns toward the unaware astronaut in utter silence it's far more terrifying than if there'd been some "wub wub" engine sound or whatever.

Happens every time a "space" movie comes out. Been seeing these guys since Star Wars in 1977 with "Um...excuse me, but there's no sound in space thank you very much....".

It's a fricken thriller movie. Just sit back and enjoy it. If you get too butthurt over the inaccuracies, then you must be a riot at parties.

I was in the 6th grade when "Star Trek" first appeared on TV but even as a geeky kid, I knew the "whoosh" made by the Enterprise in the opening credits was fake. Gene Roddenberry admitted years later he knew it was wrong, but it improved the viewer's experience. Seeing a spaceship fly silently across the screen wasn't very dramatic, then or now (well, maybe with the exception of "2001").

There's an old saying about science fiction that people are prepared to suspend their disbelief for the impossible (Woohoo! Warp Drive!) but you lose them very quickly when you introduce the extremely improbable (Woohoo! I hacked into the NSA in 12 seconds while getting a blow job by guessing an analyst's cat's name!).

I suspect most of what will offend here is not the impossible (flying from the Hubble to the ISS) but rather the improbable (haven't seen the movie so I don't have an example, but no doubt there will be plenty of em).

That's kinda what I was thinking but I had it as a (probably bad) analogy with the Uncanny Valley. When most of the film is so close to accurate, it just makes the inaccurate bits jump out more.

Great article, but during the first few paragraphs I found myself wondering something: Does NASA have an official Acronym Implementation Manager (AIM) responsible for the official Acronym Naming Department (AND), with oversight of the Acronym Management Process (AMP) and maintaining the Acronym Description Directory (ADD)?

I am not a rocket scientist, just a Kerbal Space Program player. The other major factor in an orbital rendezvous besides having enough delta-v is timing. Let's say Clooney does have just enough propellent in his magic rocket pack.

They probably would have needed to wait some non zero number of orbits for the timing on their maneuvers to be right. They most likely would have run out of air before even using their propellent.

You could just make the maneuvers right away, and get into a matching orbit, but your target would be in the same orbit on the other side of the planet from you.

Now you have to make another set of maneuvers that leave your apoapsis touching the desired orbit but lower your periapsis below it. This allows you to "catch up" to your target because as the article mentions, while you are lower in orbit you are going faster.

But then at this point you still have to usually wait a significant number of orbits to catch up, and burn more delta-v bringing your periapsis back up to the desired orbit when you do.

Another KSP player here who appreciated the shout-out in the article Actually, articles like this are one reason why I like the game so much. I wouldn't know where to start to actually calculate an orbit but I've got a reasonable mental picture of it from playing KSP - and it's much more fun if you can read stuff about space and follow some of the technicalities.

Great article, but during the first few paragraphs I found myself wondering something: Does NASA have an official Acronym Implementation Manager (AIM) responsible for the official Acronym Naming Department (AND), with oversight of the Acronym Management Process (AMP) and maintaining the Acronym Description Directory (ADD)?

Because it seems like that would be a full-time job or two...

('Cause you have to have an Acronym Definition Assistant (ADA)!)

I'm guessing you've never worked in a government agency, amIright?

Back when I worked for the Air Force (mid-90's... the last time the Gov't shut down...) I dealt with Boeing on a routine basis. They had an unofficial, R-rated acronym glossary for program reference...

Great article, but during the first few paragraphs I found myself wondering something: Does NASA have an official Acronym Implementation Manager (AIM) responsible for the official Acronym Naming Department (AND), with oversight of the Acronym Management Process (AMP) and maintaining the Acronym Description Directory (ADD)?

Because it seems like that would be a full-time job or two...

('Cause you have to have an Acronym Definition Assistant (ADA)!)

I'm guessing you've never worked in a government agency, amIright?

Or anywhere in general. Half of a new job is learning the the alphabet soup they make.

In my second job, a PSE was something we tried to create so customers would buy more stuff. In my current job, we try to avoid creating a PSE because everyone up to 27km downwind would need to evacuate.

You wouldn't have a laser battle without drawing in the lasers, because it doesn't work as entertainment.

Has anyone tried? Yes, people expect lasers to be pew-pew shiny walking-pace beams of colour thanks mailnly to Star Wars and Star Trek, but that doesn't preclude a realistic depiction being impressive. An invisibly sourceless explosion of flesh-flashed-to-steam smites anyone who looks around a corner? Terrifying! An invisible 'heat ray' causes a line of foliage to immolate advancing inexorably and quickly towards our heroes as the emitter tracks towards them? Suspense! You could even posit a hilariously powerful laser that filaments at the target region, bringing a blinding lance of plasma flashing into existence piercing the target. All seem like they'd make for dramatic and impressive scenes.

Saying a realistic depiction is impossible to make entertaining is a failure of imagination.

I remember a sweet movie from the 80s that used a hilariously powerful laser mounted to a plane, which then was used to explode a house by cooking a bunch of popcorn with said laser. at least the bulk of the lasers used in that film were in fact ACTUAL lasers and not done in post.

On the arm-spin: She goes flying away attached to about half the Canadarm. I can't find much information on exactly how much each segment masses, but the arm itself masses [url=http://www.asc-csa.gc.ca/eng/canadarm/description.asp]410kg/url]], so let's say she's attached to 200kg of arm. The Shuttle EMU masses a good 125kg all-up (but without tools), plus an average human female mass of 60kg, for a total of 185kg. That's pretty close! Back-of-the-napkin gives that the centre of rotation should be around 1/4 of the way down the arm fragment from our Bullocknaut, so ~1.9m from her (1/4 of 1/2 a 15m Canadarm). Moment of inertia would be about 670kgm^2, rotation rate at the point she detaches is about π rad/s, so an angular momentum of 2105Nms, and a release velocity of 10 m/s.

Not sure what that shows really, but that's half an hour of work I've avoided by looking up definitions I'd long forgotten!

my beef with her spinning on the canadarm was centripetal (centrifugal?) force - with that much apparent spin, how did she not black out from blood rushing to her head? i couldn't even finish watching the trailer it was so bad. yes, the graphics look amazing, (and i have to wonder whether bullock et al ever did anything other than pose for a laser scanner and then do voice acting while their digital doppelgangers did all the acting in the 100% CG sets) but i'll wait till it's on redbox or something.

at least when i took the family to go see Planes i expected implausible graphics and story, and that's exactly what we got. it wasn't trying to be serious like Gravity is, and i think that's why there are so many naysayers on this thread. someone came up with some kick ass effects, and then someone else wrote a lame story around them just to get a movie out there.

i enjoy movies for entertainment, but when they try really hard to look and seem realistic, but then do stupid stuff like this that completely shatters the illusion, it ruins it for me. i couldn't watch day after tomorrow or perfect storm for the same reason. i definitely appreciated the amount of work that went into the graphics - that took a lot of time and dedication. but the writers, directors and producers ruined it by making the entire thing feel completely contrived. at least the bruce willis asteroid one (can't recall the name offhand) had enough comedy and stuff to bring it more into the realm of star trek style storytelling instead of trying and failing to be believable.

District 9 is an example of good effects done right. it didn't scream at you to ZOMG LOOK AT OUR AMAZING FX!!!1 plus it had a halfway decent story with it. i wish more films would do their effects that way.

Great article, but during the first few paragraphs I found myself wondering something: Does NASA have an official Acronym Implementation Manager (AIM) responsible for the official Acronym Naming Department (AND), with oversight of the Acronym Management Process (AMP) and maintaining the Acronym Description Directory (ADD)?

Because it seems like that would be a full-time job or two...

('Cause you have to have an Acronym Definition Assistant (ADA)!)

I'm guessing you've never worked in a government agency, amIright?

You have no idea how easy it is to slip back into acronym/initialism mode. Dr.J (John Timmer, the science section editor) almost always has to slap every NASA-related piece I turn in with a big wet trout to shake out the majority of the acronyms; after working in that world for so many years, falling back into NASA-mode when talking about NASA stuff is easy.

I should post the audio transcript of my interview with Scoville—it's about 25% solid acronyms. Plus, we talked for abotu an hour and he gave me SO MUCH MORE awesome info than I was able to shoehorn into this report—at the very end, for example, he went on a truly beautiful engineer rant about the ISS breaking up in the trailer, talking about how the station's primary structural elements are heavy aluminum and steel and it absolutely wouldn't shatter in the fracture-pattern depicted. I also learned a ton about EVA motion speed limits, and how there's actually a hilarious NASA-only video that astronauts are shown when they start SAFER training showing what happens if they go too fast while working outside—the video consists of about fifteen minutes of astronauts on EVA missing handholds, flailing around and bumping into things.

Why is everyone so quick to try to find this movies failures? It looks to be a really exciting, and thrilling movie. Why destroy it before people see it - not based on the quality of the movie itself, but the science. Last time I checked this was not a documentary...

For me, it's the science teacher in me that goes nuts. Try as we might, it's really, really hard to get kids mind from the huge, dramatic Hollywood version of science to the often much more sedate form of real science. That's not to say that there isn't cool stuff in real science, it's just not as dramatic (go figure) as the movies.

You have no idea how many times I've had to debunk Armageddon, 2012, The Day After Tomorrow, The Core, Volcano, Dante's Peak, and just about every other disaster movie known to man. (Brosnan outrunning a pyroclastic cloud in a pickup with no tires? Yeah, not gonna happen. We would end up with crispy Brosnan long before the cool busted arm moment.)

You ever think that maybe those movies could in turn inspire a kid to get involved in the sciences? Of course they'll have to understand the way it truly work but your delivery here sounds almost as if you're shutting them down.

I just watched the movie and enjoyed it immensely! I thought it was very well done. I have always liked Sandra Bullock, and I thought she did a great job in this movie.

Not being a rocket scientist, the only time I thought they used a transfer of Earth conditions was when Bullock was hanging entangled in some cables, with Clooney hanging suspended from her via a tether. This is something you would see where gravity exerts its pull, not in space. The only thing that might have produced this effect in space would be centrifugal force, but the background was not rotating as it would if centrifugal force was in play.

Other than that, a thoroughly enjoyable movie. I felt that the producers went to great lengths to make it believable, and succeeded very well.

Yeah, Peace_Man, I couldn't figure that out either. What pulls Clooney away? Shouldn't he have bounced right back towards the ISS once his momentum was arrested, the same way that the Soyuz does later when it's parachute is tangled? But it was more like something was exerting a continuous pull on him. Is there something I missed?

Lee Hutchinson / Lee is the Senior Reviews Editor at Ars and is responsible for the product news and reviews section. He also knows stuff about enterprise storage, security, and manned space flight. Lee is based in Houston, TX.